We are requesting funds to purchase a Becton Dickenson FACSAria high speed cell sorter. The requested configuration includes three lasers, enabling the detection as many nine different fluorochromes with a range of excitation and emission properties. The instrument also includes capabilities for the collection and temperature control of single sorted cells. The new instrument will be used for a number of analysis and sorting applications in support of NIH-funded projects. These applications include multiplexed immunofluorescence analysis of cell signaling molecules, sorting of leukocytes from animal tissue, and the screening of yeast display libraries for high affinity antibodies and polypeptides. The new instrument will be housed in the LJBI Flow Cytometry Facility. Policies for access and use have been formulated, and an institutional commitment is in place to support personnel and maintenance for the initial three years of operation. The FACSAria plays a key role in the development of an advanced flow cytometry development and application capability at LJBI. [unreadable] [unreadable]